We are utilizing the change in lipid bilayer membrane impedance conductance upon the addition of antibodies to a solution containing the corresponding antigen as a means of measuring the concentration of antibody in an unknown solution. A first step is the development of a test chamber and electronic impedance meter which is more sensitive and convenient than currently available. The next step is the optimization of the membrane forming solution for improved stability and response. A more detailed study of the electrical response is being undertaken which will include the determination of the response as a function of antibody and antigen concentration.